It is known to provide heat exchanger assemblies that incorporate a metallic header and a plastic end tank with a gasket being disposed therebetween to provide a fluid-tight seal at the end tank-to-header joint. Known gaskets are not secured to either the header or the end tank but rather the gasket is placed in the header where it is not accurately positioned. This technique is disadvantageous. The gasket will only provide a fluid-tight seal if the gasket is properly positioned on the end tank. The process of mechanically attaching the gasket to the surface of the header may result in misalignment of the gasket, thereby causing defective assemblies that have to be either reassembled or scrapped.
To overcome the disadvantages of not securing the gasket, one known tank-to-header joint employs a gasket that is adhered to the end tank by means of a molding technique. In joints of this type, the end tank is formed with a slot that has deformable projections along the sides of the slot. The gasket is then molded directly to the end tank, the molding process forcing the gasket material to deform the projections such that the projections serve as retaining members for keeping the gasket attached to the end tank. This method is costly and complicated. Therefore, there exists a need for a simple and economically advantageous method of forming the end tank-to-header joint wherein the gasket is integrated with end tank while maintaining the proper alignment of the end tank, gasket and header.